The present invention relates to a laryngoscope, especially for introducing a tube into the trachea, having a laryngoscope spatula of substantially straight shape and a handle.
A laryngoscope of this kind is generally known.
A laryngoscope is a medical instrument that serves to visually observe the larynx. In anesthesia, such a laryngoscope is simultaneously used for introducing a tube, for example an anesthetic tube, with the aid of the laryngoscope into the patient""s trachea under visual control in order to be able to supply the patient with air during anesthesia. The process of introducing a tube into the trachea can be considerably simplified by a laryngoscope.
A laryngoscope was described for the first time in 1895, and was used for the first time for intubation of a patient under visual control in 1912. Since then, the use of laryngoscopes for tracheal intubation under visual control has become an essential practical part of anesthesia and in intensive medical treatment.
Up to 1943, laryngoscopes with straight laryngoscope spatulas were in use. It was the first time in 1943 that Mackintosh described a laryngoscope with a curved laryngoscope spatula, which was used in laryngoscopy in combination with a novel application technique. Since then, the use of the curved laryngoscope has established itself as standard process, because the method after Mackintosh is easier to apply with an average patient than a method using a laryngoscope with straight laryngoscope spatula. Another reason is seen in the fact that many anesthetists did not arrive at the optimum method with a straight laryngoscope since they introduced the laryngoscope through the mouth centrally, over the back of the tongue. This method formerly used is little successful with most of the more difficult patients.
In contrast, the method after Mackintosh has proved to be very successful. Unfortunately, however, it does not allow visual observation of the larynx with 2% to 5% of all patients. With these patients, tracheal intubation can be achieved by a xe2x80x9cblindxe2x80x9d process without visual control. However, blind processes are connected with a plurality of risks, including the risk of a major trauma of tissue involved.
Problems encountered in connection with tracheal intubation are a main reason for fatalities under anesthesia. One has estimated that in the western world 600 fatalities annually occur as a result of problems encountered during tracheal intubation. In addition, other major complications, such as damage to the brain, the trachea, the esophagus and other tissue, may lead to fatalities.
Although there are a number of possibilities to overcome the difficulties connected with intubation, all blind methods are connected with significant fault rates. The ideal method should be relatively simple, make use of simple equipment and provide a high rate of success, and a low fault rate.
An optimally suited method (paraglossal straight laryngoscopy) of tracheal intubation for these patients has been described by the inventor of the present invention in 1997. The method described provides a high rate of success where the method after Mackintosh fails. Unfortunately, however, no laryngoscope is available at present that can be used for that method without any disadvantages.
Two problems are encountered in difficult tracheal intubation: The first problem consists in the necessity to observe the larynx, the second in the necessity to introduce the tube through the larynx and into the trachea.
The straight laryngoscope used most frequently is the laryngoscope after Miller. When this laryngoscope is used for the paraglossal method, it is usually successful where the method after Mackintosh fails. However, manipulation of the tube to be introduced requires that an additional space be opened along the tube. This in turn requires an increased lifting pressure. Such increased lifting force cannot always be achieved, and may in addition have a traumatic effect. In addition, the configuration of the laryngoscope as such also impairs the manipulation of the tube to be introduced.
There have been known further laryngoscopes (for example after Kleinsasser, Holinger, Benjamin) which permit good visual observation of the larynx with difficult patients. However, in these cases introduction of the tube is complicated and requires a plurality of steps and much time, which may be critical with difficult patients.
Another known laryngoscope, the PCV laryngoscope, permits easy introduction of the tube. Unfortunately, however, this laryngoscope does not present an optimum configuration. It comprises a curvature which on the one hand facilitates the introduction of the laryngoscope, while making visual inspection of the larynx unsatisfactory with most of the difficult patients. In addition, the configuration of the tip impairs the desired best possible control of the epiglottis. The light carrier projects into the lower side of the laryngoscope, where tissue pressure is exerted by the laryngoscope spatula, whereby the risk of a tissue trauma is increased. In addition, the PVC laryngoscope is cost-intensive.
As has been mentioned before, the laryngoscope after Mackintosh, used most frequently, is curved along its lengthwise axis. However, it is realized more and more that such configuration is connected with a higher fault rate in tracheal intubation than is the case with laryngoscopes with straight laryngoscope spatulas.
It is, therefore, the object of the present invention to improve a laryngoscope of the before-mentioned kind in such a way that the laryngoscope will permit improved visual control of the larynx and, at the same time, improved introduction of the tube through the larynx and into the trachea.
According to the present invention, this object is achieved by a laryngoscope, in particular for introducing a tube into a trachea of a patient, comprising:
a handle; and
a laryngoscope spatula connected to said handle, said laryngoscope spatula having a longitudinally substantially straight shape, and, further being configured, at least in part, as a tubular hollow body having a proximal end and a distal end,
wherein said tubular hollow body comprises a lateral longitudinal opening extending from said distal end to said proximal end, and,
wherein said laryngoscope spatula comprises at its distal end a substantially flat tip adjacent to said distal end which is in transverse direction substantially straight.
Compared with the known laryngoscopes, the tubular configuration of the laryngoscope spatula according to the invention provides the advantage that insertion of a tube into the trachea with the aid of a laryngoscope is considerably simplified. The tube can be introduced, according to a basic method, either directly through the lumen of the laryngoscope spatula or indirectly under visual control, using an introduction aid, likewise through the lumen of the laryngoscope spatula. Unlike the known laryngoscopes, it is not necessary with this way of introducing the tube, rendered possibly by the tubular configuration of the laryngoscope spatula, to open a free space on the side of the laryngoscope, whereby the lifting force required is reduced. Consequently, the tube can be introduced less traumatically and with success even with difficult patients. The laryngoscope spatula is, however, not configured as a fully closed tubular hollow body, but is provided with a longitudinal opening in its lengthwise direction. The laryngoscope spatula according to the present invention therefore can be described as a slotted tube. The lateral longitudinal opening leads to further considerable advantages of the invention. On the one hand, the lateral longitudinal opening permits improved visual observation of the area of the larynx during introduction of the tube. The longitudinal opening enlarges the field of vision so that binocular observation is rendered possible. On the other hand, the lateral longitudinal opening also facilitates removal of the laryngoscope after the tube has been inserted, as the laryngoscope spatula can be stripped off laterally from the tube. In addition, the lateral longitudinal opening also permits introduction of the tube into the laryngoscope spatula sized in the circumferential direction. In combination with the straight design of the laryngoscope spatula, optimum observation of the larynx is achieved even with difficult patients.
By means of the flat tip at the distal end, the laryngoscope spatula is not tubular, but rather flat at its distal end. This is of advantage on the one hand for achieving optimum control of the epiglottis. On the other hand, the field of vision for visual observation, especially for visual observation of the larynx, is further increased, and visual control of the introduction of the tube is improved. This feature also leads to improve control of the epiglottis, in that the laryngoscope spatula transitions from a tubular cross-section to a plate-like cross-section in its distal area.
In a preferred embodiment of the invention, the laryngoscope spatula is approximately circular in cross-section.
It is an advantage of this configuration that the tube, which is to be introduced into the trachea and which usually is circular in cross-section, can be guided with more ease in the laryngoscope spatula.
According to further preferred embodiment, the cross-section of the laryngoscope spatula tapers in a proximal area of the tubular hollow body.
Given the fact that the laryngoscope spatula is introduced into the patient""s mouth, where the proximal area comes to lie between the patient""s teeth, this provides the advantage to reduce the risk of damage to the teeth. The tapering configuration of the proximal area of the laryngoscope spatula reduces the contact between the laryngoscope spatula and the teeth when lifting or lowering the laryngoscope spatula.
According to a further preferred embodiment, the lateral longitudinal opening of said tubular hollow body widens toward the proximal end of said tubular hollow body.
This feature provides the advantage that the tube can be introduced into the lumen of the laryngoscope spatula with more ease. In addition, the enlargement of the longitudinal opening also facilitates the action of stripping-off the laryngoscope from the tube once the tube has been introduced into the trachea.
According to a further preferred embodiment, the lateral longitudinal opening has an opening angle, viewed in cross-section, in the range of approximately 180xc2x0 to approximately 90xc2x0.
Within this angular range of the opening angle of the longitudinal opening, viewed in cross-section, the tube to be introduced can on the one hand be safely introduced into the laryngoscope spatula and guided, while on the other hand the longitudinal opening permits an increased field of vision and facilitates the removal of the laryngoscope spatula from the tube after insertion of the tube into the trachea.
It is further preferred if the tip is in longitudinal direction slightly curved or straight.
According to a further preferred embodiment, the point extends approximately over the whole width of the laryngoscope spatula.
This feature provides the advantage that the tip is a planar extension so that the risk of a tissue trauma in the area of the larynx is further reduced.
According to a further preferred embodiment, the tip exhibits a bead-like thicker portion.
This feature provides the advantage that the risk of damage to soft tissue is further reduced.
According to a further preferred embodiment, a light pipe, whose output end opens into the lumen of the laryngoscope spatula, is guided along the laryngoscope spatula.
Accordingly, the light pipe, consisting for example of a fiber bundle received in a small tube, is guided in this embodiment from the proximal end of the laryngoscope spatula to the distal end of the laryngoscope spatula, and the light-emitting end of the light pipe ends at the distal end of the laryngoscope spatula in the lumen of the laryngoscope spatula, whereby illumination of the field of observation in the area of the larynx is advantageously further improved since the propagation of light is not obstructed by tissue, especially soft tissue, in contact with the laryngoscope spatula. The light emitting end of the light pipe is directed in such a way that optimum illumination of the larynx is achieved.
According to a further preferred embodiment, the proximal end of the laryngoscope spatula comprises a mounting section for locking the handle on the laryngoscope spatula.
This provides the advantage that the laryngoscope spatula can be designed as disposable unit, while the handle, containing the light source, can be reused. However, it is also possible to design the laryngoscope spatula in such a way that it can be mounted undetachably together with the handle. Standard handles comprising a fiberoptic system can be used. When using a standard handle, the laryngoscope according to the invention can be produced at low cost.
According to a further preferred embodiment, the lumen of the laryngoscope spatula is adapted to the diameter of the tube to be introduced.
This provides the advantage that the laryngoscope according to the invention is always adapted to the particular tube size. It is then possible to have available different laryngoscopes of differently sized cross-section of the laryngoscope spatula in order to always have available the optimum laryngoscope for the respective application.
According to a further preferred embodiment, an insufflation channel, ending at the distal end of the laryngoscope spatula, is arranged on the laryngoscope spatula.
This insufflation channel may, advantageously, be used to insufflate oxygen, for example an intermittent oxygen jet at high pressure, so that emergency respiration can be carried out if the introduction of the tube should be delayed. The insufflation channel may also be used to administer local anesthetics to the larynx and other organs in the patient""s respiratory tract.
Further advantages will become apparent from the description that follows, and the attached drawing.
It is understood that the features mentioned above and those yet to be explained below can be used not only in the respective combinations indicated, but also in other combinations or in isolation, without leaving the context of the present invention.